He has gone from garda killer to Nordic royalty, but Darren Cahill said he wasn't nervous before he auditioned for the biggest role of his career.
The actor (25) is best known for his role as murderer Davey Webb on TV3's Red Rock.
Fans of the series saw the troublemaker show up at the grave of Supt James McKay and arouse suspicions when he was caught on CCTV furiously kicking the flowers left in honour of the fallen officer.
With his character behind bars, Darren departed the series and was snatched up by Vikings to play a prince.
"Vikings is going great, I'm really enjoying it. We've been filming for a few months now in Wicklow," he said.
"I play a prince, but that's all I can say. It's very hush-hush. It's completely different to Red Rock. I've gone from a murderer to a prince.
"The audition was fine. Like any audition, they're hard. I don't really get nervous, I stay calm. This is definitely my biggest role to date."
Vikings is inspired by the sagas of Ragnar Lothbrok, a legendary Norse hero and notorious as the scourge of England and France.
The show portrays Ragnar as a farmer who rises to fame thanks to successful raids into England and eventually becomes a Scandinavian king.
The series, a joint Irish-Canadian production, films in Co Wicklow and was first broadcast in 2013.
Cahill is set to star alongside fellow Irishman Moe Dunford, who plays Aethelwulf on the show.
Vikings has proved to be a hit with viewers worldwide, drawing millions of viewers in the US and Australia.
Jonathan Rhys Meyers is also set to star in the upcoming fifth season of the show, but the details of his character are being kept under wraps.
While earlier seasons had only 10 episodes, season five is set to be super-sized, with 20 episodes airing next year.